The following article was originally published in CoJen, the customer magazine by GE Energy’s Jenbacher gas engine business.
In agriculture and waste management, the use of organic waste products in biogas plants is opening up undreamed-of potential for the generation of electricity and heat. Germany, for instance, is taking a leading role in these international efforts with its renewable energy law. Numerous countries are following this example, and biogas plants are achieving a boom never seen before.
What do Austrian wine growers, a Thai palm oil producer, a U.S. dairy farm and a Pakistani biofuel producer have in common? Quite simply, they all produce tons of organic waste that can be used to generate biogas. “I really don’t like using the term ‘waste’ when we are talking about residue from agricultural production. Rather, we see it as a valuable source of energy, where the objective is to make good use of it,” says Thomas Elsenbruch, Marketing Program Manager for GE’s Jenbacher gas engines.
Following nature’s example
Biogas is a natural, purely ecological product that is extracted from biomass at biogas plants. When organic waste material undergoes anaerobic fermentation – a controlled decomposition process – a mix of gases is given off that consists of 50 to 70% methane (CH4) and 30 to 50% carbon dioxide (CO2), depending on the makeup of the source material. Almost all organic substances can be transformed into biogas in this way, although the yield may vary significantly based on the source material. For example, a ton of chicken manure can produce 50 m3 of biogas. The same amount of pig manure will yield only 21 m3 of biogas.
Biogas is an especially high-value fuel that is ideally suited for running gas engines. The energy produced can be used either for the company’s own electricity needs or can be fed into the public power grid. The heat generated is typically used as heat supply for the plant. And finally, the material left over from the fermentation process is used as a high-quality fertilizer in agriculture. GE’s Jenbacher business, supplying biogas-fueled gas engines for such applications, has been an international leader in the field for more than 30 years. The number of delivered engines has now grown to more than 1,500 units – and growth has accelerated rapidly in recent years.
From “manure lakes” to “energy lakes”
With 1,100 milk cows, the Norwiss dairy farm appears quite similar to countless others in the “dairy state” of Wisconsin. Every day, the animal residents of the farm produce an incredible 70,000 liters of liquid manure, which are stored in so-called “manure lakes.” Apart from the unpleasant odor, these vast amounts of liquid manure caused by the density of cattle in the U.S. make up approximately 15% of anthropogenic methane emissions. The Norwiss farm differs from the area’s other farms in one respect: By using the biogas gained from the fermentation of cow manure for power generation, the “manure lakes” have been turned into “energy lakes.” The farm now not only completely covers its own energy needs, it also supplies 600 households with reliable electricity. The original rethinking in this case took place on a small scale. Now, Wisconsin is expected to introduce changes at the state level that could lead the U.S. to a greener future.
The most plentiful oil in the world and what it is used for in Thailand.
In terms of volume, at more than 42 million metric tons, more palm oil is produced than any other plant oil in the world. It is used primarily in the food, cosmetic and aluminum industries, but it can also be mixed with diesel or converted directly to biodiesel.
Planting oil palms is very promising because the industry boasts a particularly high yield per acre – one of the main reasons for the popularity of palm oil farms around the world. There is a dark side, however: The oil production process generates huge quantities of organic waste material that, if not processed, has a negative impact on the ecological balance of the region. Natural Palm Oil Ltd. in southern Thailand has made a long-term goal of recycling the waste material from its palm oil mills. Two Jenbacher gas engines are already supplying 33,000 Thai households reliably with electricity. Recently, an order was placed for a third engine.
“We are very pleased with both power plants’ results. The high reliability of Jenbacher gas engine on-site power technology convinced us to install another Jenbacher unit for our power plant production capacity expansion at the Chumporn mill,” said Preecha Kuansongtham, Director of Natural Palm Oil Ltd.
High-proof power supply
In Pakistan, a Jenbacher gas engine found its way to a local ethanol factory run by Shakarganj Mills Ltd. It is used there to convert the biogas incurred in the production of ethanol from sugar cane into electricity. As a renewable energy project, the plant is eligible for carbon credits because it enhances energy efficiency at the mill and displaces the national grid’s energy generated from fossil fuels. By using the biogas instead of fossil fuels for power generation, the plant is expected to produce approximately 20,000 tons of certified emission reductions annually. However, the potential is far greater. “With 225 million liters of ethyl alcohol produced annually in Pakistan, we expect many other distillery companies to install similar plants to support the energy needs of the national grid,” said Kashif Kazmi, Project Manager for the plant.
A clean affair: countries promote biogas
These are just a few of the types of organic waste that can be turned into hard cash. In addition to the more traditional applications, such as utilizing sewage gas in wastewater treatment plants, new opportunities are constantly developing.
So why has demand grown so rapidly only in recent years? The answer is simple: Thus far, biogas plants have only been able to compete with the price of power generated using conventional sources of energy, such as nuclear energy, hydropower or calorific power, under certain circumstances. In order to be economically competitive, the state has to provide assistance with fixed power prices to biogas plant operators, at least for a certain period. “More and more countries now recognize that the benefits of ecological and autonomous power supply are a huge advantage and are following the example of Germany,” Thomas Elsenbruch explains. The German Renewable Energy Sources Act (EEG) took effect in 2000 and promotes the expansion of power and heat generation using renewable energies. The idea is to offer operators of plants using renewable energy sources a fixed price for the power they generate for a certain period of time. The EEG and its revisions of 2004 and 2009 have been decisive in promoting power generation using renewable energy in Germany.
Today, the German law is already considered a huge success story and, as a result, served as a model for 47 other countries, including the Italian government, which has issued so-called “certificati verdi” (green certificates) for power generation using renewable energy sources. These certificates are transferable commercial instruments verifying that the power generated comes from renewable energy sources. In Eastern Europe and the emerging countries of Asia, efforts are increasing to promote the expansion of biogas plants by guaranteeing certain prices for electricity.
Achieving the Kyoto goals with biogas
From an international perspective, the Kyoto Protocol also plays an important role in the construction of biogas plants. Since 2005, companies that produce more greenhouse gases than the specified threshold values have been required to pay fines – unless they buy emission certificates from other companies that produce less greenhouse gases than the permitted levels. One emission certificate corresponds to one metric ton of saved CO2-emissions and can be sold.
A sewage plant in South Africa can earn 33,000 emission reduction certificates a year, which corresponds to the same amount in CO2-equivalents saved. A farm with three million chickens in China can save as much as 95,000 metric tons of CO2-equivalents. Obviously, Jenbacher is proud that so many of its customers are making a verifiable contribution to reducing CO2-emissions around the world and are at the same time helping their companies lower their energy costs and recycle waste in a responsible and effective way.